1. Field of the Invention
The present invention relates to an electronic device, and in particular, to an electronic device having a magnetic body made by magnetic powders.
2. Description of Related Art
An electronic device functions as stabilizing current in a circuit and filtering noises. The function of an electronic device is similar with that of a capacitor—they both adjust the stability of current by storing and discharging the electric power in the circuit. While a capacitor stores the electric power in a form of an electric field (electric charge), an electronic device does the same in a form of a magnetic field. There are energy losses in conducting wires and magnetic core (usually called “core loss”) when it comes to the application of an electronic device.
In related art, a conducting wire of an electronic device is buried inside a magnetic body. The method of manufacturing this kind of electronic device is to firstly place the conducting wire in a mold, to fill in the mold with iron powder which includes an adhesive and is in the similar size of the particle diameter to cover the conducting wire, and to compress the iron powder into the magnetic body by means of a pressure molding. Then, the adhesive is heated up to be cured. The permeability of the electronic device with its magnetic body made of iron powder will slump in a high frequency above 10 KHz. Therefore, the conventional electronic device cannot be applied in the practice of high frequencies.
Furthermore, an annealing process which is generally performed above 600° C. is necessary to reduce the strains of magnetic powders when more than two magnetic powders of different sizes are mixed to form a magnetic body.
Accordingly, the present invention proposes the structure of the electronic device and its manufacturing method to overcome the above-mentioned problems.